This invention relates to a coil winding for a DC machine and more particularly to an improved, simplified and lower cost coil-winding assembly for such machines.
It has been the practice to provide a coil winding for DC machines wherein the winding core is comprised of radially spaced inner and outer annular elements. The armature cores are formed as extending teeth on one or the other of these elements. As is well known, the core is preferably formed from a plurality of laminated electromagnetic steel plates such as silicate steel or the like. The outer periphery of the inner element is shrunk fit into the inner periphery of the outer element so as to form a complete assembly.
Prior to this, however, coil windings are formed on the core teeth. This is frequently done by placing insulating bobbins around which the coils have been wound on the core teeth before the two elements are shrunk fit together.
Although this expedient provides a very good assembly, there are some difficulties, which may arise. The shrink fit, for example, may result in imprecise axial positioning between the two elements. This problem is aggravated by the lamination of the elements.
In order to maintain the elements in their position, it has been proposed to bond the elements to each one once they have been shrunk fit. This is generally done by embedding them in a resin material. However, this still does not provide a rigid enough connection. For example, this type of mechanism is frequently used as a DC motor to power a wheel of a vehicle. The vibrations associated with such applications however, can cause a slipping between the elements and affects the coupling accuracy between the bobbins and the magnetic poles.
In addition, it is frequently the practice to embed or immerse the electric motor in oil for improving its cooling. However, the lubricating oil used may attack the resin employed for the bonding and cause the connection to become weakened.
It is, therefore, a principal object to this invention to provide an improved coil winding for an electric machine wherein the coil winding can be formed from interconnected radially inner and outer annular elements, one of which has extending core teeth.
It is a further object to this invention to provide a more rigid location arrangement for locating the inner and outer elements relative to each other that does not necessarily require adhesive bonding.
With the aforenoted construction, it is necessary to connect the coil windings to each other in a predetermined fashion and to supply or extract electrical power from them in a timed sequence when phased windings are employed. This requires a contact plate or wiring board to which the coil ends are connected. Previously, these windings boards have been mounted separately and complicate the arrangement for making the wiring connections.
It is, therefore, a still further object to this invention to provide an improved coil winding for an electric machine wherein the associated wiring board can be conveniently and rigidly mounted relative to the windings and thus improve the physical retention of the elements relative to each other.
In connection with extracting the wiring from the coil windings and connecting it to the control circuit, there is a risk that the coil ends can become loose and shift. This will cause the entire winding to loosen and may result in breaking of the electrical connections.
It is, therefore, a still further object to this invention to provide an improved bobbin arrangement for use with a coil winding of this type and wherein the bobbins provide a retainer assembly for retaining the ends of the wires of the coil windings.
A first feature of this invention is adapted to be embodied in an electrical coil winding assembly for a rotating electrical machine. The winding assembly comprises a core that is formed of annular radially inner and outer elements, which form a plurality of radially extending armature cores. Electrical coils are wound around the armature cores. Circumferentially spaced and radially extending interengaging parts on the core elements maintain the axial relationship between the core elements.
Another feature of the invention is also adapted to be embodied in an electrical coil winding assembly for a rotating electrical machine. In accordance with this feature of the invention, the winding assembly comprises a core that is formed by annularly radially inner and radially outer elements forming a plurality of radially extending armature cores. Each of a plurality of bobbins surrounds a respective one of the armature cores. Electrical coils are wound around each of the bobbins. The bobbins and respective electrical coils are detachably connected to the core element that forms the armature cores by retaining clips. At least some of the retaining clips have end portions that extend in an axial direction beyond the core elements and a wiring plate is carried by such retaining clip end portions.
Yet another feature of the invention is also adapted to be embodied in an electrical coil winding assembly for a rotating electrical machine. The assembly comprises a core that is formed by annular, radially inner and radially outer elements that form a plurality of radially extending armature cores. Each of a plurality of bobbins around which the respective electrical coils are wound surrounds a respective one of the armature cores. The bobbins have portions that form a retainer for retaining the conductor ends of the respective coils against movement.